I suppose that in the small puzzles, the crux is in what I call the
dynamic topology. I mean by this the patterns of stones
moving around in rooms
and opening and closing spaces for the man temporarily.

"Nuclear
Fission" by Mic (G4B)
Example for dynamic topology

This I contrast with the
fixed topology. That means the design of the walls and rooms,
which obviously
don't change and so are more accessible to logical analysis.

Sokowahn #13
by Mic (G4B)
Example for fixed topology

In particular, in small puzzles it gets hard when there are at least
a couple
of sealed-off areas the man cannot get to most of the time, and the
solution
variations involve switching from one sealed-in arrangement (or
component ) to another but avoiding deadlock. It is hard to
analyse these
component access problems logically as you have to store in your memory
lots of different arrangements and how to reach them -
the correct variations can then be very well hidden amongst similar
but
deadlocked positions. In other words, there is more potential to fool
people.

It is the patterns of space the man can reach in different variations
that you have to try to remember, which is something you could not
predict
from the start position of the puzzle, plus you have to remember
sequences of moves which open up a hole to get through to a component.

It gets really hard if you have to open up a hole and then close it
behind you,
since there is then lots of potential for small differences in stone
positions
on one side or the other of the hole making the difference between
carrying on to a solution or getting deadlocked.

I find it helpful sometimes to work out that certain stones have special
roles,
such as opening and closing a hole, so I can work out what changes
have to be
made to avoid deadlock. Then it gets even more difficult if a stone
has to
change roles (as in the Dual Barricade).

"Dual Barricade"
by Masato Hiramatsu (hir)

Another problem I have with these kinds of puzzle: even if I solve them
I am
not quite sure what I did, and may find it just as hard coming back
to the
puzzle: whereas with puzzles where the problems are mostly fixed topology
it is not too hard to remember my logical analysis and be able to solve
them quickly
at any later time.